Ancient bacteria have preserved 145 million-year-old tree trunk fossils in Dorset's Fossil Forest.
The remnants of late Jurassic cypress trees can be found in the Fossil Forest in Dorset,
a section of the southern English coastline dotted with live limestone mounds.
The Jurassic Coast, a 95-mile (153-kilometer) section of southern England's coastline
that is dotted with fossils from the Jurassic period (201 million to 145 million years ago),
is home to the 145 million-year-old Dorset Fossil Forest.
Because of hordes of microscopic, algae-like bacteria that quickly colonized the dead trees,
the Fossil Forest is home to some of the most unusual fossils on the Jurassic Coast.
These colonies created living limestone mats known as thrombolites that are still
discernible today by trapping and coating calcium carbonate particles onto the trees
over the eons. The Jurassic-Cretaceous border,
which marks the end of the Jurassic epoch, is when the now-fossilized forest grew.
Temperatures and sea levels decreased during this boundary, revealing new land and
creating coastal plains that supported the growth of new species, including trees.
As the water receded, ancient conifer, tree-fern, and cycad species grew on what is now
England's southern coast.
According to the website Geology of the Wessex Coast, which is operated by Ian West,
a geologist and visiting scientist at the University of Southampton in the United Kingdom,
dinosaurs may have roamed the forest at this time in Earth's history, but flowering plants
had not yet formed.
Sea levels quickly rose again, drowning the trees in saline water, therefore the forest
was short-lived.
However, bacteria maintained the roots and trunks instead of allowing them to decay away.
The Fossil Forest is made up of spherical mounds known as "algal burrs" that remain on
the shoreline after the trunks of the trees eventually broke off.
No tree trunks are still present at the Fossil Forest site, although a few have been
discovered preserved along the Jurassic Coast.
According to the Jurassic Coast Trust, this is probably because Victorian tourists
looted them.
Halfway up a cliff overlooking the English Channel are the algae burrs of the Fossil Forest.
According to West's article on Geology of the Wessex Coast, the majority of the woody
remains found inside the burrs are from an old species of cypress known as
Protocupressinoxylon, and they are still anchored in prehistoric soil.
Therefore, according to West, the Fossil Forest "provides information on an ancient
ecosystem in which late Jurassic dinosaurs lived."
By Sascha Pare
Source livescience.com
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